Modern sensor systems, when subjected to external stimuli, produce signals that can be directly read at the output of the sensor systems, or further processed and then directed to a downstream system. The variety of stimuli modern sensor systems are designed to sense includes sound, temperature, weight, position, electric current and voltage, light, color, speed of motion, magnetic field, pressure, and geometrical shapes of two and three dimensions, foreign substances in solutions such as blood, urine, etc. Among modern sensors, Hall-effect sensors (Hall sensors) are designed to sense the presence and to measure the strength of magnetic fields, or other measurable that can be converted to magnetic field.
One type of known Hall sensor systems measures magnetic field continuously and outputs measured data continuously. With this type of Hall sensors, the sensing portion (e.g., the Hall plate) and the data processing portion of the sensor system are powered on continuously to maintain continuous measurement and output. Most linear Hall sensors belong to this type.
A second type of known Hall sensor systems measure magnetic fields sporadically or periodically. In contrast to the linear Hall sensor, this second type of Hall sensor is suitable for applications where only occasional readings of the magnetic field are required. This type of Hall sensor normally remains powered off except during the short periods when measurements are called for. During these short periods, the sensing portion and the data processing portion of the sensor are both powered on so measurement is taken and the measurement data are processed and displayed. Outside the period window, no measurement is taken and no measured information can be gleaned from the system.